How to detect if URL has changed after hash in JavaScript

I wanted to be able to add locationchange event listeners. After the modification below, we’ll be able to do it, like this

window.addEventListener('locationchange', function () {
    console.log('location changed!');
});

In contrast, window.addEventListener('hashchange',() => {}) would only fire if the part after a hashtag in a url changes, and window.addEventListener('popstate',() => {}) doesn’t always work.

This modification, similar to Christian’s answer, modifies the history object to add some functionality.

By default, before these modifications, there’s a popstate event, but there are no events for pushstate, and replacestate.

This modifies these three functions so that all fire a custom locationchange event for you to use, and also pushstate and replacestate events if you want to use those.

These are the modifications:

(() => {
    let oldPushState = history.pushState;
    history.pushState = function pushState() {
        let ret = oldPushState.apply(this, arguments);
        window.dispatchEvent(new Event('pushstate'));
        window.dispatchEvent(new Event('locationchange'));
        return ret;
    };

    let oldReplaceState = history.replaceState;
    history.replaceState = function replaceState() {
        let ret = oldReplaceState.apply(this, arguments);
        window.dispatchEvent(new Event('replacestate'));
        window.dispatchEvent(new Event('locationchange'));
        return ret;
    };

    window.addEventListener('popstate', () => {
        window.dispatchEvent(new Event('locationchange'));
    });
})();

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Note, we’re creating a closure, to save the old function as part of the new one, so that it gets called whenever the new one is called.